1. Field of the Invention
The present invention relates to a method for manufacturing a probe for irradiating with or detecting light and to such a probe. More specifically the present invention relates to a method for manufacturing a probe for irradiating with or detecting evanescent light that is used especially in near-field optical microscopes and the like, and to such a probe and to a surface-observing apparatus having the probe.
2. Related Background Art
Since a scanning tunnel microscope (hereafter called xe2x80x9cSTMxe2x80x9d), which can directly observe an electron structure of surface atoms of a conductor, has been developed (G. Binning et al., Phys. Rev. Lett, 49, 57 (1982)), and actual space images can be measured at high resolution whether single crystalline or amorphous, a scanning probe microscope (hereafter called xe2x80x9cSPMxe2x80x9d) has been studied hard in the field of evaluating the microstructure of materials. SPMs include a scanning tunnel microscope (STM), an atomic force microscope (AFM), and magnetic force microscope (MFM), which detect surface structures using tunnel current, atomic force, magnetic force, light and so forth obtained by approaching a probe having a micro-tip to a sample to be evaluated. As a developed type of STM, a scanning near-field optical microscope (hereafter abbreviated as SNOM), which detects evanescent light oozing out from an optical micro-aperture on the tip of a sharp probe using an optical probe to study the surface of a sample, has been developed (Durig et al., Appl. Phys., 59, 3318 (1986)).
Furthermore, one type of SNOMs, Photon STM, to observe the surface of a sample by making an incident light from the back of the sample through a prism under a total-reflection condition come through the sample and detecting the evanescent light coming out to the surface of the sample with an optical probe, has also been developed (Reddick et al., Phys. Rev. B39, 767 (1989)).
Optical probes used in the above-described near-field optical microscopes include one using an optical fiber with a sharpened end to which an optical micro-aperture is provided, and another using a tip for irradiating with or detecting light fixed to the free end of a cantilever to impart the function as an AFM.
As such a cantilever-type probe, one having at the tip of a protrusion an optical micro-aperture formed by processing the end of an optical fiber, and imparting the function of bending as a cantilever to the optical fiber, has been disclosed (U.S. Pat. No. 5,677,978). However, in the methods using optical fibers, productivity is low, because probes must be processed one after the other, and it is difficult to make the same shape. Therefore, a method for fabricating a probe, in which a light-permeating protrusion formed on a first substrate is transferred onto a wave guide layer formed on a second substrate, a light-shielding layer is formed over the surface of the protrusion, and an optical micro-aperture is formed on the tip of the light-shielding layer (Japanese Patent Application Laid-Open No. 10-293134). Since this method is a batch process, the productivity of probes is high, and the process reproducibility of the optical micro-apertures is high. Also, the integration and down sizing of the probes are easy, and a plurality of probes can be fabricated easily. Furthermore, the method is advantageous in that the transferring of the protrusion to a compound semiconductor substrate enables the probe to be coupled easily with a semiconductor laser.
However, in the probe disclosed in Japanese Patent Application Laid-Open No. 10-293134, since the protrusion having an optical micro-aperture and the wave guide layer are fabricated separately and are optically coupled in the following process step, the process for forming such an optical coupling portion between the wave guide layer and the optical micro-aperture is complicated, and the transmission efficiency of light in the coupling portion is more or less poor.
Therefore, the object of the present invention is to solve the above-described problems, and to provide a method for manufacturing a probe for irradiating with or detecting light, which is possible by a batch process with high productivity, has the high process reproducibility of optical micro-apertures, facilitates integration and down sizing, enables a plurality of probes to be fabricated easily, enables fabrication on compound semiconductor substrates, does not need any optical coupling portion between a wave guide layer and an optical micro-aperture, and minimizes the transmission loss of light; and a probe for irradiating with or detecting light; and a surface-observing apparatus having the probe.
The above and other objects are achieved by:
a method for manufacturing a cantilever-type probe for irradiating with or detecting light having a protrusion that has an optical micro-aperture and a wave guide layer, which comprises the steps of forming the protrusion and the wave guide layer integrally on one substrate, and transferring the integrally formed protrusion and wave guide layer to another substrate;
a method for manufacturing a probe for irradiating with or detecting light, which comprises the steps of:
(a) forming at least one recession on a first substrate;
(b) fabricating a probe structure that contains a wave guide layer on the first substrate with the above recession;
(c) bonding the probe structure on a second substrate;
(d) transferring the probe structure that has a protrusion onto the second substrate, by peeling the probe structure off the first substrate; and
(e) forming a cantilever-type probe that has a protrusion on a free end thereof by removing a part of the second substrate; and
a cantilever-type probe for irradiating with or detecting light having a protrusion that has an optical micro-aperture and a wave guide layer manufactured by the above method for manufacturing the probe; and
a surface-observing apparatus having the cantilever-type prove for irradiating with or detecting light.